Automatic electric controlling system.



No. 768,868. PATENTED AUG. 30, 1904.

W. STOGKMEYER. AUTOMATIC ELECTRIC CONTROLLING SYSTEM. W

APPLICATION nun MAR.1B. 1902. no MODEL. 2 SHEBTBSHEET 1.

MAMA

No. 768,868. PATENTED AUG. 30, 1904. W. STOGKMEYER.

AUTOMATIG ELECTRIC CONTROLLING SYSTEM.

APPLICATION FILED MAR. 18. 1902.

N0 MODEL. 2 SHEETS-SHEET 2.

WWE

upon the auxiliary source.

UNITED STATES Patented August 30, 190 1.

PATENT ()EEicE.

AUTOMATIC ELECTRIC CONTROLLING SYSTEM.

SPECIFICATION forming part of Letters Patent No. 768,868, dated August 30, 1904. Application filed March 18, 1902. Serial No. 98,832. (No model.)

To all whom, it nuty concern:

Be it known that I, TVILHELM S'rocKMEYER, a subject of the German Emperor, and a resident of 259 Uainzer Landstrasse, Frankforton-the-Hain, Germany, have invented certain new and useful Improvements in Automatic Electric Controlling Systems, of which the following is a specification.

lVhereas there exist very simple and sensitive instruments for indicating even small variations of electric current and voltage, no simple apparatus has hitherto been known which will act as a regulator when such variations occur-for instance, by putting a resistance into or out of circuit or by operating a steam-valve or a switch. The automatic pressurecontrollers hitherto used, for instance, for the most part act indirectly, a relay-circuit being closed by acontact-voltmeter and the relay operating an electromagnetic coupling device which couples the contact-lever of the regulating-resistance with a shaft driven by a motor.

The object of the present invention is to provide highly sensitive arrangements which will by reason of their sensitiveness possess considerable adjusting or controlling power even when slight variations from the normal pressure occur, so that they can generally be used without auxiliary apparatus and power.

The invention consists in placing the coil of the electrom agnet actuating the instrument not directly under the pressure which is to be regulated, but only under the difference between this pressure and the pressure from another current-generator or auxiliary source acting in the opposite direction, the circuit containing the coil and the auxiliary source being of such resistance that the current flowing in the circuit has approximately no effect The principle of operation is similar to that in the system of compensation used for measuring purposes or potentiometer method of measuring. The

pressure from the one current-generator is subject to fluctuations, whereas the pressure from the other generator is to a considerably higher degree constant. The smaller the difference between this constant pressure and the normal pressure of the first current-generator the more sensitive will the instrument be. coil of the electromagnet is dead, and the instrument remains at rest. hen the pressure from one of the generators rises or falls, current passes through the coil toward or from the other generator, so that the electromagnet operates and continues to operate the regulating device as long as difference of pressure exists between the two generators.

The resistance of the coil is so chosen that the current passing through it from or toward the second current-generator while the greatest difference of pressure exists will not reduce or increase the pressure from the second generator or will only do so to a slight and admissible extent. The regulation of the pressure can either be eii'ected for its own sake or for some ulterior purpose.

Figures 1, 2, and 3 of the annexed drawings illustrate three diagrams for the purpose of explaining the invention.

l/Vith the arrangement shown in Fig. 1 the object is not the regulation of pressure for its own sake, but the regulation of the speed of a marine engine. The shunt-dynamo (I, which is driven by the main shaft, is connected by the wires I and l to an accumulator against the electromotive force of which it acts. The solenoid g, which is adapted to operate a steam-valve, exliaustwalve, distributing-gear, or other controlling device directly or with the aid of auxiliary apparatus worked by steam or the like, is provided with two coils. The upper coil consists of a large number of turns of thin wire and the lower coil of a small number of turns of thick wire. One of these coils polarizing the armature of the solenoid is joined up as a shunt between the terminals of the dynamo or the accumulator, the other being placed in the conductor l in such a manner that a charging-current will increase the influence of the upper coil on the iron core k, whereas a discharging-current will reduce or nullify the said influence. By overcoming the counteracting force of the spring Z: the iron core it directly operates a throttle-valve in the steam-pipe by means of the double-armed lever J, the connecting-rod Z, and the lever m. If, for in- As long as the pressures are equal the stance, the propeller breaks, an increase of ten per cent. in the speed of the main engine would send a powerful charging-current into the accumulator. This would cause the core it to be pulled into the solenoid, and the steamvalve would be closed sufficiently to prevent the engine from acquiring a dangerous degree of speed. If the speed of the engine increases by less than, say, ten per cent, the charging-current is too weak to cause the solenoid to overcome the force of the spring in. If the solenoid were made with only one coil connected to the terminals of the dynamo, the force with which the core is attracted would only increase in approximately direct proportion with the speed of the engine.

Owing to the considerable and varying friction which has to be overcome in operating the steam-valve, the latter would in some cases be operated too soon, in other cases too late.

The ordinary fluctuations of boiler-pressure and changes of water-level in the boilers do not cause the apparatus described to interfere with the working of the engine in any way, since the electromotive force has to increase, say, about ten per cent. before a stronger current goes into the accumulator. However, when the electromotive force increases beyond this by even a small amount a powerful charging-current is at once produced, owing to the low resistance of the accumulator, and the solenoid is caused to close the steam-valve, even though a large amount of friction requires to be overcome.

An example in which the regulation of pressure is effected for its own sake is shown in Fig. 2, which diagrammatically illustrates means for regulating a current generator.

The shunt-dynamo a supplies an illuminating installation with current through the mains I and II. By the wires III and IV and the coil it an accumulator 7) is joined up to act against 1 the dynamo. The electromotive force of the accumulator corresponds to the normal pressure in the illuminating system. The iron core 0, which is polarized by the pressure-coil (Z, is pivoted to the contact-arm of the shuntregulator e. As long as the electromotive force of the dynamo is equal to that of the accumulator?) no current flows in the coil 7t, and the contact-arm remains stationary. When the electromotive force of the dynamo increases, however. a charging-current passes through the coil to the accumulator 6, the core 0 is pulled farther into the coil, and the contactarm is moved in the direction which causes the degree of excitation to be lowered, whereupon the electromotive force of the dynamo falls. If the electromotive force of the dynamo is too low, current passes through coil [L from the accumulator, the core 0 is pushed out, and the degree of excitation of the dynamo increased, so that the electromotive force increases to its normal value. To prevent overregulation, a stop to the iron core can be provided. The fact that the accumulator itself by receiving and giving ofi current can keep the load. and thereby the pressure of the machine, constant within certain limits is not essential to the purpose of my invention. The size of the accumulator is independent of the size of the dynamo and of the entire installation. It must be so chosen that the current which passes through the coil it while the greatest distance of pressure exists will effect the pressure from the accumulator but little or not at all. Instead of an accumulator any other equivalent current generator can be used which possesses the required clectromo tive force and not too great resistance. Instead of the parts It, 0, and (Z an electromotor can be used, the magnet-coil taking the place of the coil h and the armature-coil taking the place of the coil (Z, suitable transmission-gear being provided between the motor-shaft and the contact-arm.

The arrangement shown in Fig. 3 will show the advantage of my invention for operating a switch besides controlling a resistance. The dynamo a, driven by a carriage-axle, is used for illuminating railway-cars, the pressure from the said dynamo being rendered by known or novel means, within wide limits independent of the speed of the train. hen the voltage required for the lamps is reached, the automatic interrupter b connects one pole of the machine over the wires I and II with the contact-spring 0 and the coil 9' of the electromagnet 2.. The other end of this coil is connected to the contact-spring (Z. The other terminal of the dynamo is connected by the wire III with the lamp-switch it and the accumulators i and 70, which are connected to the brushes e f. The exciting-coil of the dynamo is connected 'to this switch it by the wire IV in such a manner that the dynamo only gives current when the lamps are switched on. In the conductor IV the resistance-coil Z is placed. When the cylinder 0 is in the position shown in the drawings, this resistancecoil Z is short-circuited by the wire V, the brushes m and 92, and the contact-surfaces of the said cylinder. The latter and'the lever 22 are keyed to the shaft q, whereas the ratchet wheel 'r and the contact-drum s, with which the said ratchet-wheel is integral, are loosely mounted on the said shaft. The lever p is connected with the armature of the electromagnet 25.

The action of the apparatus is as follows: As soon as the train, and with it the dynamo a, acquire a speed which produces the voltage required by the lamps the automatic switch 6 comes into operation. Owing to the resistance of the coil g, the greater part of the current from the dynamo passes over the brushes 0 and e to the accumulator 2". A small portion of the current passes through the coil 9 to the lamps. The rest of the current required by the lamps is supplied by the accumulator is over the brushes (Z and f. When in consequence of the charging the pressure at the accumulator i and at the dynamo increases, the current in the coil 9 rapidly increases until the armature of the magnet t is attracted and the eontact-cylindero is rotated in such a manner as to break contact of the brush m and place the resistance-coil Z in the exciting-circuit of the dynamo. The pressure from the dynamo is thus caused to fall, so that only a weak current continues to charge the accumulator a. As soon as the speed or the train is reduced the automatic interrupter b breaks the circuit of the dynamo. For a short time a small current continues to flow from the accumulator a" through the coil g;

, but when the pressure from the said accumulator has become approximately equal to that from the accumulator 7t" and the coil 9 is left almost without current the armature of the magnet 2, falls. A pawl on the lever 22 operates the ratchet-wheel r and rotates the drum 5 through sixty degrees, so that the chargebattery 2 is placed in circuit with the lamps by the brushes 0 and d, and instead of the accumulator a" the discharged accumulator 71" is charged over the brushes f and a during the next run of the train. At the same time the resistance-coil Z is short-circuited again.

The following calculation will, as an example, show the advantage with regard to sensitiveness of the arrangement described over an arrangement in which the coil of the electromagnet is formed of a tension-coil connected to the terminals of a dynamo. Let the resistance of the coil g be four ohms, the P. D. at the lamps thirty-two volts and at the dynamo forty volts, the current in the coil 9 will then be 1 if the P. n. at the I 2 amperes.

dynamo raises to forty-one volts, the current wn I 2.25 amperes. An increase of the other system would therefore in this case be five times that of the known apparatus. The variety of the examples described will show that it is not possible to exhaustively deal with the applicability of my invention in detail. It is sharply distinguished from the known arrangements which are placed between two currentgeneratorsfor instance, from the known automaticmaximum or minimum interrupters, since the purpose of these is to prevent a too large or too small current without regard to the pressure at the currentgenerators. They act solely as safety devices.

I declare that what I claim is- 1. In an automatic electric controlling system, the combination with a main current-generator, of mains for the working current connected thereto, an auxiliary current source having a substantially constant electromotive force which is approximately equal to the nor mal pressure of said main generator and opposed thereto, a coil, connections whereby said auxiliary source and said coil are connected in series across said mains, and a regulator operatively related to said coil, the resistance of the'circuit containing said coil and auxiliary source being such that the current flowing therein has approximately no effect upon said auxiliary source.

2. In an automatic electric controlling systom, the combination with a main current-generator, of a second currentgenerator comprising two accumulators, a lamp-circuit, connections between the main current-generator and the accumulators of the second current-generator and lamp-circuit, whereby the accumulators may be charged by the main currentgenerator and discharged into the lamp-circuit alternately, a resistance, a switch and an elec tromagnet and means operated thereby, whereby the resistance may be inserted in the exciting-coil of the main current-generator whenthe electroniotive force of the accumulator being charged increases and whereby the accumulators may alternately be placed in the circuit with the lamps, the parts having the general mode of operation and being constructed and arranged substantially as specitied.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

WILHELM S"O(JKMEYER. \Vitness es:

FRANZ 'HAssLAoii n11, MICHAEL VOLK. 

